냉찜질 팩의 화학 원리

질산암모늄의 흡열 용해 연구하기

Thermochemistry Beginner (Middle School) 20 분 ~$6.00

목표

질산암모늄이 물에 용해될 때의 온도 변화를 측정하여 즉석 냉찜질 팩에 사용되는 흡열 용해 과정을 실증한다.

배경

Ammonium nitrate dissolves endothermically in water, absorbing heat from the surroundings and causing a significant temperature drop. This principle is used in commercial instant cold packs for first aid. The dissolution has ΔH = +25.7 kJ/mol.

안전 경고

  • Ammonium nitrate is an oxidizer — keep away from organic materials and heat
  • Do not mix with anything other than water for this experiment
  • Wear goggles

필수 개인 보호 장비

goggles

재료

  • Ammonium nitrate (NH₄NO₃) (30 g)
    Or from a commercial cold pack
  • Distilled water (100 mL)
    Room temperature

장비

Polystyrene cup calorimeter Thermometer Stirring rod Analytical balance

실험 절차

1

Add 100 mL of distilled water to the polystyrene cup calorimeter. Record the initial temperature.

3 분
2

Weigh 30 g of ammonium nitrate.

2 분 Ammonium nitrate is an oxidizer
3

Add the ammonium nitrate to the water. Stir gently to dissolve.

3 분
4

Record the temperature every 30 seconds as it drops. Note the minimum temperature.

5 분
5

Feel the outside of the cup — it should feel cold.

1 분
6

Calculate ΔH of dissolution per mole: q = mcΔT, n = mass/M(NH₄NO₃), ΔH = q/n.

5 분

예상 결과

Temperature should drop 15-20°C. 30 g NH₄NO₃ = 0.375 mol. q = 100 × 4.18 × ΔT. Calculated ΔH should be approximately +25 kJ/mol (±15%).

정리

The ammonium nitrate solution is safe to dispose down the drain (dilute). Rinse the calorimeter.

세부 정보

카테고리
Thermochemistry
난이도
Beginner (Middle School)
소요 시간
20 분
예상 비용
$6.00
단계
6
재료
2

더 많은 실험

아세트산나트륨의 발열 결정화 30 min 마그네슘의 연소열 50 min 금속의 비열 용량 40 min 커피컵 열량 측정 40 min 헤스의 법칙 검증 60 min 얼음의 융해 엔탈피 25 min 용해는 항상 발열이 아니다 25 min 폭탄 열량계 시뮬레이션 45 min 흡열 반응 실험 20 min

Frequently Asked Questions

What is the objective of 냉찜질 팩의 화학 원리?
질산암모늄이 물에 용해될 때의 온도 변화를 측정하여 즉석 냉찜질 팩에 사용되는 흡열 용해 과정을 실증한다.
How difficult is 냉찜질 팩의 화학 원리?
This experiment is rated as Beginner (Middle School). It takes approximately 20 minutes to complete.
What safety precautions are needed for 냉찜질 팩의 화학 원리?
Key safety precautions include: Ammonium nitrate is an oxidizer — keep away from organic materials and heat; Do not mix with anything other than water for this experiment; Wear goggles.
What materials are needed for 냉찜질 팩의 화학 원리?
The main materials required are: Ammonium nitrate (NH₄NO₃), Distilled water.
What results should I expect from 냉찜질 팩의 화학 원리?
Temperature should drop 15-20°C. 30 g NH₄NO₃ = 0.375 mol. q = 100 × 4.18 × ΔT. Calculated ΔH should be approximately +25 kJ/mol (±15%).